CPPropertyAnimation.j

/*
 * CPPropertyAnimation.j
 * AppKit
 *
 * Created by Nicholas Small.
 * Copyright 2008, Nicholas Small.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/*
  A VERY basic, but functional, property for Cappuccino. This is not CoreAnimation,
  nor anything similar. However, it will handle some basic property animations, and
  more can easily be added.
*/

@implementation CPPropertyAnimation : CPAnimation
{
	CPView _view;
	CPString _keyPath;
	
	CPValue _start;
	CPValue _end;
}

- (id)initWithView:(CPView)aView property:(NSString)keyPath
{
	self = [super initWithDuration:1.0 animationCurve:CPAnimationLinear];
	if(self)
	{
		if([aView respondsToSelector:keyPath]){
			_view = aView;
			_keyPath = keyPath;
		} else {
			return null;
		}
	}
	
	return self;
}

- (void)setCurrentProgress:(float)progress
{
	[super setCurrentProgress:progress];
	
	progress = [self currentValue];
	
	if(_keyPath == 'width' || _keyPath == 'height')
        progress = (progress * (_end - _start)) + _start;
    else if(_keyPath == 'size')
        progress = CGSizeMake((progress * (_end.width - _start.width)) + _start.width, (progress * (_end.height - _start.height)) + _start.height);
	else if(_keyPath == 'alphaValue')
		progress = (progress * (_end - _start)) + _start;
        
	[_view setValue:progress forKey:_keyPath];
}

- (void)setStart:(id)aValue
{
	_start = aValue;
}

- (id)start
{
	return _start;
}

- (void)setEnd:(id)aValue
{
	_end = aValue;
}

- (id)end
{
	return _end;
}

@end

Example.j

var opacityAnimation = [[CPPropertyAnimation alloc] initWithView:aLabel property:@"alphaValue"];

[opacityAnimation setStart:0.0];
[opacityAnimation setEnd:1.0];
[opacityAnimation setDuration:0.5];

[opacityAnimation startAnimation];